"Stamped from the beginning"
Kendi's title is taken from an 1860s speech by Jefferson Davis, who said that the "inequality of the white and black races was stamped from the beginning." This phrase is used as a symbol of historical racist attitudes and the ideas that races are inherently different. For Kendi, this phrase also has a modern application as black people are still disadvantaged in America from birth.
The Human Genome Project
The Human Genome Project showed that "in genetic terms, all human beings, regardless of race, are more than 99.9 percent the same," which makes it a symbol of the true equality that exists between people, that isn't held up in society. This project was historically used to challenge biological racism, showing that there was no genetic difference between black and white people.